Potensi Bakteri Endofit dari Berbagai Tanaman untuk Mengendalikan Meloidogyne spp. pada Tanaman Terung (Solanum melongena L.)

Abstract

Nematoda puru akar (NPA) yang disebabkan oleh Meloidogyne spp. merupakan salah satu penyakit penting pada tanaman terung. Pengendalian Meloidogyne spp. menggunakan nematisida sintetik merupakan pengendalian yang paling banyak diminati oleh petani karena lebih praktis dan mudah didapatkan. Penggunaan nematisida sintetik yang tidak bijaksana dapat menyebabkan resistensi patogen dan pencemaran lingkungan. Keberhasilan bakteri endofit dalam mengendalikan penyakit tular tanah telah banyak dilaporkan. Bakteri endofit merupakan bakteri yang hidup di jaringan tanaman yang dapat meningkatkan pertumbuhan dan kesehatan tanaman inang. Penggunaan bakteri endofit yang diisolasi dari tumbuhan Lantana camara L. serta isolat bakteri endofit asal sawit, pinang, mangrove dan paku-pakuan diharapkan dapat menekan NPA sekaligus memacu pertumbuhan tanaman terung. Penelitian ini bertujuan untuk mengevaluasi keefektifan bakteri endofit dalam menekan populasi Melodogyne spp. serta pengaruhnya terhadap pertumbuhan tanaman terung. Penelitian ini dilaksanakan di Laboratorium Nematologi Tumbuhan dan Laboratorium Bakteriologi Tumbuhan serta Rumah Kaca Cikabayan IPB dilaksanakan bulan November 2020 hingga Maret 2022. Penelitian ini mencakup isolasi dan seleksi bakteri asal L. camara, menggunakan isolat koleksi asal kelapa sawit, pinang, mangrove dan paku-pakuan, uji karakterisasi fisiologi bakteri endofit, uji mortalitas nematoda terhadap bakteri endofit dan uji mortalitas nematoda dengan senyawa volatile organic compound (VOC) asal bakteri endofit secara in vitro, pengujian keefektifan bakteri endofit di rumah kaca, dan karakterisasi molekuler bakteri endofit terbaik. Data dianalisis menggunakan rancangan acak lengkap (RAL) dengan uji Tukey pada data uji in vitro dan uji Dunnet pada data uji in vivo pada taraf 5%. Sebanyak 48 isolat bakteri endofit berhasil diisolasi dari tumbuhan L. camara. 23 isolat diantaranya tidak bersifat patogen terhadap tumbuhan dan mamalia. Berdasarkan karakterisasi fisiologi, sebanyak 12 isolat menghasilkan enzim protease, kitinase dan pelarutan fosfat dan 6 isolat diantaranya memproduksi enzim kitinase dengan indeks kitinolitik sebesar 0,33-1,16. Hasil pengujian terhadap mortalitas juvenile 2 Meloidogyne spp. 8 isolat menghasilkan persentase mortalitas sebesar 34,3-96,2%. Lima isolat terpilih dari hasil pengujian mortalitas diuji secara in vivo dan uji VOC yaitu LCA5, LCA13, LCA19, EG26 dan BAT27. Berdasarkan hasil pengujian di rumah kaca, perlakuan lima isolat potensial dapat menurunkan kerusakan akar dan telur Meloidogyne spp. pada tanaman terung. Penekanan kerusakan akar tertinggi ditunjukkan oleh isolat LCA5+LCA13. Kelima isolat yang digunakan berpengaruh nyata terhadap tinggi dan bobot basah tanaman terung. Perlakuan isolat LCA19 menunjukkan pertumbuhan yang lebih baik dibanding perlakuan isolat lain. Hasil pengujian VOC menunjukkan isolat LCA13 memilki pengaruh mortalitas tertinggi terhadap juvenil 2 Meloidogyne spp. Berdasarkan sekuens gen 16S rRNA, tiga isolat memiliki identitas berturut-turut teridentifikasi sebagai: Dyella marensis LCA5, Stenotrophomonas rhizophilla

Root-knot nematode (RKN) caused by Meloidogyne spp. is one of the important diseases of eggplant. Control of Meloidogyne spp. using synthetic nematicides is the most in demand by farmers because it is more practical and easy to obtain. The unwise use of synthetic nematicides can lead to pathogen resistance and environmental pollution. The success of endophytic bacteria in controlling soil borne diseases has been widely reported. Endophytic bacteria are bacteria that live in plant tissue that can increase the growth and health of host plants. The use of endophytic bacteria isolated from Lantana camara L. and isolates of endophytic bacteria from oil palm, areca nut, mangrove and ferns is expected to suppress NPA as well as stimulate eggplant growth. This study aims to evaluate the effectiveness of endophytic bacteria that can suppress the population of Melodogyne spp. and its effect on plant growth of eggplant. This research was carried out atthe Plant Nematology Laboratory and Plant Bacteriology Laboratory IPB and Cikabayan, Greenhouse IPB from November 2020 to March 2022. This study included the isolation and selection of bacteria from L. camara, using isolates collection from oil palm, areca nut, mangrove and ferns, isolation of Meloidogyne spp. physiology characterization test of endophytic bacteria, nematode mortality test against endophytic bacteria and nematode mortality test with volatile organic compounds (VOC) in vitro, testing the effectiveness of endophytic bacteria in greenhouse, and molecular characterization of the best endophytic bacteria. Data were analyzed using a completely randomized design (CRD) with the Tukey and Dunnet test at the 5% level. Fourthy-eight bacterial endophyte isolates were successfully isolated from L. camara. 23 isolates of which are not pathogenic to plants and mammals. Based on physiological characterization, as many as 12 isolates each produced protease, chitinase and phosphate solubilizing enzymes, 6 of which produced chitinase enzymes with a chitinolytic index of 0.33-1.16.The test results of eight isolates on mortality of juvenile 2 Meloidogyne spp. produce a percentage of 34.3-96.2%. Five isolates selected from the mortality test results were tested in vivo and VOC tests, namely LCA5, LCA13, LCA19, EG26 and BAT27. Based on the results of testing in a greenhouse, the treatment of five potential isolates could reduce the scale of damage to roots and eggs of Meloidogyne spp. on eggplant plants. The highest suppression of root damage was shown by isolates LCA5+LCA13. The five isolates had a significant effect on the height and wet weight of eggplant plants. Treatment of LCA19 isolates showed better growth than other isolates. The results of the VOC test showed that LCA13 isolate had the highest mortality effect on juvenile 2 Meloidogyne spp. Based on the 16S rRNA gene sequence, three isolates were identified as: Dyella marensis LCA5, Stenotrophomonas rhizophilla LCA13, Providencia vermicola LCA19